Gate valve

ABSTRACT

A gate valve comprising a valve housing with connection openings disposed in mutually opposite relationship on a first common axis, and also connection elements for the inlet and outlet of a fluid, a cap on the valve housing and a valve actuation means coupled to a sliding gate. It is provided therein that arranged in the valve housing are: a hollow cage having a first and a second end face of which the first end face has an insertion opening, further with two mutually oppositely disposed fixed side walls and two parallel mutually oppositely disposed free side walls which are formed by two separate side plates with through bores which in the installed condition are on a second common axis, the sliding gate which has a through-flow opening is introduced through the insertion opening of the cage and is guided sealingly in the cage and between the side plates and the side plates bear with their respective inward side in surface contact against the sliding gate, the sliding gate has two end positions so that in a first opened end position the through-flow opening of the sliding gate coincides completely with the diameter of the through bores of the side plates in the installed condition and in a second closed end position the through-flow opening of the sliding gate is completely outside the diameter of the through bores of the side plates.

The invention concerns a gate valve comprising a valve housing withconnection openings disposed in mutually opposite relationship on afirst common axis, and also connection elements for the inlet and outletof a fluid, a cap on the valve housing and a valve actuation meanscoupled to a sliding gate.

Gate valves are known in many different configurations. Conventionalshallow-wedge sliding gates have a wedge-shaped shut-off member whichwhen the valve is closed is pressed into a wedge-shaped receiving means.In that case the degree of sealing integrity is dependent on the contactpressure. When the valve is opened, deposits, so-called incrustations,are formed, which accumulate when the wedge member is closed and arepressed into the wedge-shaped receiving means. The result of this can bethat the valve must firstly be closed with a greater contact pressureand also that it no longer closes completely at all.

In the present case the object is to provide a gate valve in whichdeposits forming from the flow of fluid in the valve no longer collectin the valve housing and can no longer adversely affect the closingfunction of the valve.

That object is attained in that arranged in the valve housing are ahollow cage having a first and a second end face of which the first endface has an insertion opening, further with two mutually oppositelydisposed fixed side walls and two parallel mutually oppositely disposedfree side walls which are formed by two separate side plates withthrough bores which in the installed condition are on a second commonaxis, that the sliding gate which has a through-flow opening isintroduced through the insertion opening of the cage and is guidedsealingly in the cage and between the side plates and the side platesbear with their respective inward side in surface contact against thesliding gate, that the sliding gate has two end positions so that in afirst opened end position the through-flow opening of the sliding gatecoincides substantially or completely with the diameter of the throughbores of the side plates in the installed condition and in a secondclosed end position the through-flow opening of the sliding gate iscompletely outside the diameter of the through bores of the side plates.Advantageous developments are described in the appendant claims.

In that respect it is preferred for the side plates and the sliding gateto comprise ceramic, the cage to comprise a plastic material and thevalve housing, the connection elements and the cap to comprise castmetal or to be hot-pressed or forged. The fact that the side plates aremounted in a plastic cage makes it possible to guarantee precisepositioning of the ceramic plates relative to each other.

It is further preferred that the second end face of the cage has acylindrical concave curvature and the curvature forms the connection ofthe fixed side walls. Preferably at their one end the side plates followthe contour of the curvature and are inserted into the free side wallsof the cage.

In addition the side plates are preferably of a mirror-imageconfiguration and the first common axis of the mutually oppositelydisposed connection openings, in the installed condition, coincides withthe second common axis of the through bores in the separate side plates.

In a preferred embodiment each of the side plates has a projection inthe form of a rib which extends around the through bore and whichengages into the connection openings of the valve housing or into theconnection elements disposed therein. The engagement of the separateside plates into the connection openings of the valve housing or intothe connection elements disposed therein is preferably sealed off bymeans of flat seals and/or O-rings. In that way, a slight prestressingcan be produced on the ceramic plates by means of the flat seals whilethe O-rings provide for static sealing integrity.

Preferably the sliding gate has an abutment element for limiting themovement of the sliding gate. In a preferred configuration the abutmentelement is a transverse bar which comprises cast metal or is hot-pressedor forged and which is pushed through a transverse opening in thesliding gate and held there. Precise stroke movement limitation ispossible by means of the transverse bar.

In a preferred embodiment, in the first opened end position of thesliding gate an abutment for the movement of the sliding gate is formedby a projection in the cap, against which projection the transverse barbears, and in the second closed end position of the sliding gate afurther abutment for the movement of the sliding gate is formed by theexposed upper face of the valve housing, against which the transversebar bears.

In a further preferred configuration, in the first opened end positionof the sliding gate an abutment for the movement of the sliding gate isformed by abutment pins which are screwed into the transverse bar andwhich butt against the exposed upper face of the valve housing and inthe second closed end position of the sliding gate a further abutmentfor the movement of the sliding gate is formed by a projection in thecap, against which projection the transverse bar bears.

Preferably at least one of the side plates on the side that is towardsthe sliding gate has a passage which with its one end opens into therespective through bore in the side plate and which in the second closedend position of the sliding gate opens with its other end in thethrough-flow opening in the sliding gate.

The valve actuation means preferably has a spindle which engages intothe transverse bar and the sliding gate preferably has a blind bore forreceiving the spindle. The spindle is preferably a screwthreaded spindlewhich is held axially immovably in a bearing in the cap and which isscrewed with a screwthreaded portion into the transverse bar. The gapbetween the spindle and the bearing in the cap is preferably sealed offby means of an O-ring.

That structure provides for better long-term sealing integrity. Inaddition that structure makes it possible to use the advantages ofceramic materials such as for example resistance to corrosion, a smallamount of wear and low weight insofar as it permits a simple connectionof the spindle to the ceramic sliding gate and an exact position for theend positions of the valve. In addition the component parts are easy toproduce and by virtue of simplicity of structure are suitable formachining by automatic equipment. That additionally affords costadvantages in terms of manufacture.

The invention however not only attains that object but also has furtheradvantages. Thus, even after a long period of no use, the closing forcesof the valve are low in contrast to conventional valves which, by virtueof corrosion, are difficult to move after a prolonged period of notbeing used. The preferred configuration with a passage in the insidesurface of a side plate also affords the advantage that the valve isdead water-free and frost-resistant if the passage is on the dischargeflow side of the valve and the connection region is beneath thethrough-flow opening so that the fluid can flow away out of thethrough-flow opening.

The invention is described in greater detail hereinafter by means ofembodiments and with reference to the drawings in which:

FIG. 1 shows an exploded view of a valve in a first embodiment,

FIG. 2 a shows a view in longitudinal section through a valve of thefirst embodiment in the opened position,

FIG. 2 b shows a view in longitudinal section turned through 90° throughthe valve of FIG. 2 a,

FIG. 3 shows an exploded view of a valve in a second embodiment,

FIG. 4 a shows a view in longitudinal section corresponding to FIG. 2 aof the second embodiment,

FIG. 4 b shows a view in longitudinal section turned through 90° throughthe valve of FIG. 4 a,

FIG. 5 a shows a view in longitudinal section corresponding to FIG. 4 athrough the valve in the closed position, and

FIG. 5 b shows a view in longitudinal section corresponding to FIG. 4 bthrough the valve in the closed position.

In the description hereinafter of the embodiments by way of example,terms such as ‘left’, ‘right’, ‘top’, ‘bottom’, ‘inner’, ‘outer’,‘vertical’ or ‘horizontal’ relate to the illustration of the valve inthe accompanying drawings. The choice of those terms serves solely tofacilitate the present description and under no circumstances is to beinterpreted as limiting the scope of protection for the described valvescan be installed in any spatial position.

The component parts of the valve will firstly be described by referenceto the embodiments by way of example. Components involving the samefunction are referenced in the same manner in the Figures.

The valve which is intended in particular for liquids has a valvehousing 10, connection elements 12, 14 for the inlet and outlet, a cap16 on the valve housing 10 and a valve spindle 22 which is rotatable byan actuation element, for example a hand wheel 18, about a vertical axis20. In the illustrated embodiment the connection elements 12, 14 arearranged on a common horizontal axis 24. Arranged within the valvehousing are a cage 26, two side plates 28, 30 to the right and the leftof the cage 26, a sliding gate 32 between the side plates 28, 30 and atransverse bar 34 in the sliding gate 32.

The valve housing 10 which comprises cast metal or is hot-pressed orforged has four side faces, comprising two mutually opposite closed sidefaces 36, 38 and two further mutually opposite side faces 40, 42, anupper opening 44 and a lower end face with a cylindrical concavecurvature 46 which connects the closed side faces 36, 38. The furtherside faces 40, 42 each have a respective connection opening 48, 50 witha female screwthread, into which are screwed the connection elements 12,14 which are provided with a male screwthread. Adjoining the side faces36, 38, 40, 42 upwardly is an exposed face 52 in substantiallyperpendicular relationship to the side faces 36, 38, 40, 42, which atits outside goes into an upstanding flange 54 with a female screwthread56.

The cap 16 which also comprises cast metal or can be hot-pressed orforged, in the lower region thereof, has a diameter and a malescrewthread 58 which match the upstanding flange 54 of the valve housing10. In the illustrated embodiments the two are screwed there. At apredetermined height the diameter of the cap 16 decreases so that aprojection 60 is formed in the interior of the cap 16. Above theprojection 60 the diameter further reduces to an upper bore 62. Theoutside wall of the cap 16 is of a hexagonal configuration in the regionof the upper bore 62 so that it can be screwed to the valve housing 10by means of a screw wrench.

The spindle 22 which also comprises cast metal or is hot-pressed orforged includes, viewed from below upwardly, a screwthreaded portion 64,an annular flange 66, a cylindrical sealing portion 68 with a groove 70,a further screwthreaded region 72 and a connection portion 74 which fromits free end is at least partially provided with a screwthread 76. Theannular flange 66 prevents a movement of the spindle 22 which is guidedfrom below through the bore 62 upwardly out of the cap 16. A movement ofthe spindle 22 downwardly out of the cap 16 is prevented by a nut 78which is screwed on to the screwthreaded region 72. The sealing portion68 is thus axially immovably guided in the bore 62 of the cap 16. AnO-ring 80 is arranged in the groove 70 for affording sealing integrity.

To rotate the spindle 22, in the illustrated embodiment a hand wheel 18is fitted from above on to the spindle and fixed with a nut 82 which isscrewed on to the screwthread 76.

The hollow cage 26 comprises plastic material and in the firstembodiment in the installed condition terminates below the exposedsurface 52 of the valve housing 10. In the second embodiment the cage26, in the installed condition, projects into the cap 16, but no furtherthan the length of the abutment pins 120, 122 which are describedhereinafter in the second embodiment. The cage 26 has two end faces ofwhich the upper end face has an insertion opening 84 and the lower endface has a cylindrical concave curvature 86. In addition the cage 26 hastwo mutually opposite fixed side walls which are connected by thecurvature 86. In addition the cage 26 includes two parallel, mutuallyopposite free side walls which are at least partially formed by twoseparate side plates 28, 30.

The side plates 28, 30 comprise ceramic material and in the firstembodiment are completely of the same contour as the free side walls ofthe cage 26. In the second embodiment the side plates 28, 30 are notcompletely of the same contour as the free side walls of the cage but inthe installed condition terminate beneath the connection openings 48, 50of the valve housing 10.

The side plates 28, 30 are inserted into the free side walls of the cagefrom the side. Their mutually opposite flat faces are ground andpolished. In addition the side plates 28, 30 are of a mirror-imageconfiguration and each have a respective through bore 88, 90 with ahorizontal axis 92 which is common in the installed condition. Each ofthe side plates 28, 30 has a projection 94, 96 in the form of a ribwhich extends around the through bore 88, 90.

The sliding gate 32 which also comprises ceramic material is of anelongate, plate-shaped configuration and has two spaced, parallel andflat side faces 98, 100 which are ground and polished. The side faces98, 100 contact in sealing relationship the surfaces of the side plates28, 30, which are in opposite relationship in the cage 26. In otherrespects the sliding gate 32 is matched to the internal contours of thecage 26. The sliding gate 32 also has a through-flow opening 102 whichextends between the side faces and whose shape and diameter correspondsto the through bores 88, 90 in the side plates 28, 30. In the upperregion the sliding gate 32 has a transverse opening 104 for receivingthe transverse bar 34 and a blind bore 106 for receiving the spindle 22.

The transverse bar 34 which comprises cast metal or can be hot-pressedor forged is of a quadrangular cross-section in the illustratedembodiment, with a central portion 108 which is approximately square incross-section, and two flattened ends 110, 112. The cross-section of thecentral portion 108 is matched to the cross-section of the transverseopening 104 in the sliding gate 32. In addition, in its central portion108, the transverse bar 34 has a perpendicular screwthreaded bore 114.In a second embodiment (FIGS. 3 to 5) the transverse bar 34 additionallyhas in each of its ends 110, 112 a screwthreaded bore 116, 118 which isparallel to the screwthreaded bore 114.

Furthermore the second embodiment additionally has cylindrical abutmentpins 120, 122 in perpendicular relationship with the exposed upper face52 of the valve housing 10. At their upper ends the abutment pins 120,122 have a male screwthread with which they are screwed into thescrewthreaded bores 116, 118 of the transverse bar 34.

In addition, in the second embodiment, one of the side plates 28, 30, inits surface which is towards the sliding gate 32, additionally has apassage 124 in the form of a groove which opens with its one end intothe through bore 88, 90 in the side plate 30 and which extends from themouth opening location in the direction of movement of the sliding gate32 into a region of the side plate 30 which, when the valve is closed,is disposed where the through-flow opening 102 of the sliding gate 32 isto be found.

The mode of operation of the valve will now be described by reference tothe embodiments.

The cage 26 and the side plates 28, 30 which are inserted into its freeside walls are arranged within the valve housing 10 in such a way thatthe horizontal axis 92, which is common in the installed condition, ofthe through bores 88, 90 of the side plates 28, 30 coincides in theinstalled condition with the horizontal axis 24 of the connectionelements 12, 14 and the connection openings 48, 50. The projection 94,96 of each of the side plates 28, 30 engages into the connectionelements 12, 14 and sealing integrity of the connection between the sideplates 28, 30 and the connection elements 12, 14 is ensured by means offlat seals 126, 128 and O-rings 130, 132. In an embodiment notillustrated here it is possible to use flat seals or O-rings.

The sliding gate 32 is introduced into the cage 26 through the insertionopening 84 thereof and is guided between the fixed side walls of thecage 26 and the side plates 28, 30 in surface contact relationshipbearing sealingly thereagainst.

The transverse bar 34 is pushed through the transverse opening 104 inthe sliding gate 32 and held there so that the screwthreaded bore 114 inthe central portion 108 of the transverse bar 34 is on an axis with theblind bore 106 of the sliding gate 32 for receiving the spindle 22. Thespindle 22 engages with its screwthreaded portion 64 into thescrewthreaded bore 114 of the transverse bar 34.

Rotation of the axially immovable spindle 22 causes the transverse bar34 to move up and down on the screwthreaded portion 64 of the spindle22, entraining the sliding gate 32. In that way the sliding gate 32 cannow be moved up and down. The movement of the sliding gate 32 is limitedby two end positions which are established by abutments. In a firstopened end position the through-flow opening 102 of the sliding gate 32is completely aligned with the through bores 88, 90 in the side plates28, 30. In a second closed end position the through-flow opening 102 ofthe sliding gate 32 is disposed completely outside the region of thethrough bores 88, 90 in the side plates 28, 30.

In the first embodiment the first opened end position of the slidinggate 32 (FIG. 2) is established by the transverse bar 34 bearing againstthe projection 60 in the cap 16. The second closed end position of thesliding gate 32 is defined in the first embodiment by the transverse bar34 bearing against the exposed upper face 52 of the valve housing 10.

In the second embodiment the first opened end position of the slidinggate 32 (FIG. 4) is established by the abutment pins 120, 122 which arescrewed into the transverse bar 34 butting against the exposed upperface 52 of the valve housing 10. The second closed end position of thesliding gate 32 (FIG. 5) is defined in the second embodiment by thetransverse bar 34 bearing against the projection 60 in the cap 16.

In the second embodiment the valve is therefore closed when thetransverse bar 34 bears against the upper abutment 60. In that positionthe above-mentioned passage 124 communicates the dead space of thethrough-flow opening 102 of the sliding gate 32 with one of theconnection regions (through bore 88, 90 and connection elements 12, 14)of the valve. Assuming that the passage 124 is disposed on the dischargeflow side of the valve and the connection region is below thethrough-flow opening 102 the fluid can flow away out of the through-flowopening 102. Dead water in the valve and the risk of frost are avoidedthereby.

As explained hereinbefore these are possible forms of implementation butare not restricted thereto.

The invention therefore achieved the provision of a valve which can beproduced inexpensively and automatically, which is corrosion-resistantand thus easily operable even after a long period of not being used andis possibly dead water-free and frost-resistant and has precise strokemovement limitation.

1. A gate valve comprising a valve housing with connection openings disposed in mutually opposite relationship on a first common axis, and also connection elements for the inlet and outlet of a fluid, a cap on the valve housing and a valve actuation means coupled to a sliding gate, wherein arranged in the valve housing are a hollow cage having a first and a second end face of which the first end face has an insertion opening, further with two mutually oppositely disposed fixed side walls and two parallel mutually oppositely disposed free side walls which are formed by two separate side plates with through bores which in the installed condition are on a second common axis, that the sliding gate which has a through-flow opening is introduced through the insertion opening of the cage and is guided sealingly in the cage and between the side plates and the side plates bear with their respective inward side in surface contact against the sliding gate, that the sliding gate has two end positions so that in a first opened end position the through-flow opening of the sliding gate coincides substantially or completely with the diameter of the through bores of the side plates in the installed condition and in a second closed end position the through-flow opening of the sliding gate is completely outside the diameter of the through bores of the side plates.
 2. A gate valve according to claim 1 characterised in that the side plates and the sliding gate comprise ceramic and the mutually touching surfaces thereof are polished.
 3. A gate valve according to claim 1, wherein that the cage comprises a plastic material.
 4. A gate valve according to claim 1, wherein the valve housing, the connection elements and the cap comprise cast metal or are hot-pressed or forged.
 5. A gate valve according to claim 1, wherein the second end face of the cage has a cylindrical concave curvature and the curvature forms the connection of the fixed side walls.
 6. A gate valve according to claim 5 wherein at one end, the side plates follow the contour of the curvature.
 7. A gate valve according to claim 1, wherein the separate side plates are inserted into the free side walls of the cage.
 8. A gate valve according to claim 1, wherein the side plates are of a mirror-image configuration and the first common axis of the mutually oppositely disposed connection openings, in the installed condition, coincides with the second common axis of the through bores in the separate side plates.
 9. A gate valve according to claim 1, wherein each separate side plate has a projection in the form of a rib which extends around the through bore and which engages into the connection openings of the valve housing or into the connection elements disposed therein.
 10. A gate valve according to claim 1, wherein the engagement of the separate side plates into the connection openings of the valve housing or into the connection elements disposed therein is sealed off by flat seals and/or O-rings.
 11. A gate valve according to claim 1, wherein the sliding gate has an abutment element for limiting the movement of the sliding gate.
 12. A gate valve according to claim 11 wherein the abutment element is a transverse bar which is pushed through a transverse opening in the sliding gate and held there.
 13. A gate valve according to claim 11 wherein transverse bar comprises cast metal or is hot-pressed or forged.
 14. A gate valve at least according to claim 13 wherein the first opened end position of the sliding gate an abutment for the movement of the sliding gate is formed by a projection in the cap, against which projection the transverse bar bears, and in the second closed end position of the sliding gate a further abutment for the movement of the sliding gate is formed by the exposed upper face of the valve housing, against which the transverse bar bears.
 15. A gate valve at least according to claim 13 wherein at the first opened end position of the sliding gate an abutment for the movement of the sliding gate is formed by abutment pins which are screwed into the transverse bar and which butt against the exposed upper face of the valve housing and in the second closed end position of the sliding gate a further abutment for the movement of the sliding gate is formed by a projection in the cap, against which projection the transverse bar bears.
 16. A gate valve at least according to claim 15 wherein at least one of the side plates on the side that is towards the sliding gate has a passage which with its one end opens into the respective through bore in the side plate and which in the second closed end position of the sliding gate opens with its other end in the through-flow opening in the sliding gate.
 17. A gate valve at least according to claim 1 wherein the valve actuation means has a spindle, wherein the spindle engages into the transverse bar and the sliding gate has a blind bore for receiving the spindle.
 18. A gate valve according to claim 17 wherein the spindle is a screwthreaded spindle and is held axially immovably in a bearing in the cap and a screwthreaded portion of the spindle is screwed into the transverse bar.
 19. A gate valve according to claim 1 wherein the gap between the spindle and the bearing in the cap is sealed off by an O-ring. 